Some communications networks, for example, Land mobile radio (LMR) networks operating according to the Association of Public Safety Communications Officials (APCO) “Project 25” (P25) standards, use both time division multiple access (TDMA) and frequency division multiple access (FDMA) protocols. Generally, time division multiple access protocols utilize half-rate encoded voice frames, and frequency division multiple access protocols utilize full-rate encoded voice frames. Full-rate encoded voice frames take up to twice as much radiofrequency bandwidth as the half-rate encoded voice frames.
Digital vehicular repeater systems, which are often configured to use a frequency division multiple access protocol, are sometimes used to extend fixed land mobile radio networks that are configured to use a time division multiple access protocol. To communicate with a digital vehicular repeater, a two-way radio would have to use the frequency division multiple access protocol. Because that protocol requires full-rate encoded audio, the two-way radio is unable to communicate with the portion of the land mobile radio network that uses half-rate encoded audio and a time division multiple access protocol.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.